The invention concerns the technical sector of packaging machines, which are arranged downstream of machines for producing articles in order to receive the articles, order them and insert them into corresponding packagings.
In particular, the invention refers to the packaging of articles constituted by sachets or pouches for granular or liquid products, known in the trade as stickpacks, a predetermined number of which are piled and then placed in relative cartons.
In this technical sector, machines for producing stickpacks are part of the category known as “sachet-filling machines”, while the machines for placing them in cartons are known as “cartoning machines”.
The most commonly used type of stickpack filling machine is a vertical machine. The taut band which will form the stickpack is unwound from a spool and brought to the upper part of the machine. Suitable cutters divide the band longitudinally into a predetermined number of strips, all having a same width.
Each strip is fed into a relative dropping channel, in which the following are provided, in order:                folding organs, which roll the strip in the direction of its width so as to form a continuous tubular packaging;        longitudinal sealing organs, which seal the overlapping edges of the continuous tubular packaging and close the packaging;        transverse sealing organs, which are activated horizontally in a phase relation with the stepped descent of the continuous tubular packaging, dividing the internal volume of the underlying sealed stickpack from the upper stickpack in formation, which operation defines the bottom of the stickpack;        pouring organs located above the transverse sealing organs, which project into the continuous tubular packaging and dispense dosed quantities of granular or liquid product into the stickpack being formed;        cutting organs, which are activated in a phase relation with the descent of the continuous tubular packaging and separate the lowest stickpack from the continuous tubular packaging, which stickpack has been filled with the product and sealed.        
The various dropping channels, each being provided with the above-listed organs, are arranged side by side, and distanced by a constant interaxial measurement which is equal to the width of the strips; obviously the same interaxial measurement separates one stickpack from the stickpack adjacent to it, at the exit zone in the lower part of the machine.
The vertically-arranged stickpacks exiting from the machine are collected by handling organs, for example of the “pick and place” type, which have a same number of heads as there are dropping channels, and are arranged with the same interaxial measurement, which handling organs insert the horizontally arranged stickpacks into corresponding queued walled compartments of a conveyor line associated to the cartoning machine which is arranged downstream.
The pick and place cycle is repeated until a predetermined number stickpacks has been placed in each compartment.
The compartments are distanced from each other by the same interaxial measurement as the dropping channels; the walls of each compartment, as is known, are arranged at right angles relative to the direction of advancement of the line and are positioned, in the above-described application, at a slightly lower height than the height of the carton in which the batch of stickpacks will be placed.
Given the same interaxial measurement however, the distance between the walls of each compartment can vary according to the format of the carton which, in turn, will be larger or smaller according to the number of stickpacks it has to contain.
Consequently, there is no control over the position of the stickpacks when they are being placed in the compartments, therefore each batch of stickpacks arranges itself differently, firstly in the relative compartments and subsequently in a relative carton, while remaining within the same overall area.
Thus it is clearly impossible to form an ordered pile of stickpacks and keep their arrangement under control up to the moment when they are placed in the carton; this precludes the following operating modalities:                placing an ordered pile inside a precisely-sized format of carton, that is, a carton having dimensions only slightly greater than the pile itself;        placing more than one ordered pile into a precisely-sized carton;        placing more than one ordered pile into a precisely-sized carton which is provided with separators between one pile and the next.        